Incidence of intracranial bullet fragment migration

Migration of retained bullets or bullet fragments may present as a complica tion of gunshot wounds to the head. This phenomenon has been reported in ca ses of abscess formation or retained copper fragments. Management of such m igratory fragments is controversial. The purpose of this study is to determ ine the incidence of fragment migration in a population of neurosurgical pa tients treated for gunshot wounds to the head. Two-hundred and thirteen cas es treated at Detroit Receiving Hospital between 1985 and 1987 were reviewe d. Each patient treated had initial and one week follow-up imaging studies. Nine cases of documented migratory intracranial bullet fragments were iden tified Thus, the incidence in this population is 4.2%. The fragments in eig ht cases were composed of copper, and in the remaining case, lead. No case was associated with an abscess. Fragments in the anterior fossa were found to migrate towards the sella turcica, while those of the middle fossa and p osterior hemispheres migrate towards the confluence of sinuses (Torcula Her ophili). Fragment migration was documented as early as 36 h post-injury. Ba sed on this study, we recommend serial imaging studies to look for migratin g bullet fragments and surgical removal aided by intra-operative ultrasound to localize the fragment when possible.